First thing to try when it gets difficult to attach/remove disconnect is just replace the o-ring on the post. As the rubber deteriorates, it won't allow a smooth action. There's also keg lube for this, but it can make the situation even worse, as it gets stiff in the cold of your fridge/kegerator, and is petroleum-based and so accelerates the deterioration of the o-ring. O-rings are cheap, Ikeep a supply and replace them often. I can't see the post itself being a problem, but I suppose the balls and collar on the disconnect could be gummed up over time if cleaning has been lax. Disassemble and clean well before deciding you need to replace.